Drove one.
Drove a V-12 in a Pete one time it did haul a$$. However was plauged by the same problems the v-8 had "oil leaks" any many of them. The main culprit was the accessory gear box on the back of the engine. If my memory serves me correct it was rated at 525HP. Big engine in its day.
This wasn't a 92 series,it wasn't turboed. It just had a blower. It would pass everything on the highway back in the eary 70s(except of course the fuel stops)it got right at 4-5mpg. On a good day,with a tail wind. Plus it was the noisiest truck I ever drove. Detroits were a two stroke diesel and would out accelerate most rigs out there,but put them on a heavy grade the old four stroke 600 KT Cummins would eat it alive... ... ... But correct me if I'm wrong,but I believe the KT didn't come out till 75 or 76?But even the old 335 Cummins would start to close on me on a long hill.
That was the only way to get peak performance out of a Detroit was to run the rack "hot". Used to pull Wolf Creek and pull over at the top and run the rack. Lots of burn't fingers... ... ...
The Detroits were a OK engine. They would run about 300,000 miles between overhauls. "IF" you took care of them. You could throw any driver on them(no skill required,just put your foot on the floor and herd the truck down the road). That was there big selling point. The Cummins and early Cats took a little driving skill in those days. Warm ups,cool downs,monitoring gauges,and backing off when needed. Much like our bombed 5. 9s... ... .